Wafer container having electrically conductive kinematic coupling groove, support surface with electrically conductive kinematic coupling pin, transportation system, and method

ABSTRACT

A transportation system ( 100/200 ) has a wafer container ( 100 ), such as a FOUP, to rest on a support surface ( 200 ). The container has kinematic coupling grooves, and the support surface has kinematic coupling pins. Grooves and pins are at least partially electrically conductive and allow coupling an electric device ( 150 ) associated with the container to an electrical circuit ( 250 ) associated with the support surface. Device and circuit in combination allow to perform a variety of functions, such as monitoring the correct position of the container, and exchanging signals.

RELATED APPLICATION

This Application relates to the U.S. Application Ser. No. 09/641,153filed Aug. 17, 2000 entitled, “Wafer Container Having ElectricallyConductive Kinematic Coupling Groove To Detect The Presence Of The WaferContainer On A Support Surface, The Support Surface, and Method” andassigned to Semiconductor 300 Gmbtt & Co., Infineon Technologies AG andMotorola, Inc.

FIELD OF THE INVENTION

This invention relates to carriers for semiconductor wafers, and moreparticularly, relates to a container for transporting and storingwafers.

BACKGROUND OF THE INVENTION

In semiconductor industry, wafers have to be carefully carried betweenprocessing stations. Currently there is a trend to carry them in acontainer, such as, for example, in a Front Opening Unified Pod (FOUP).

FIG. 1 illustrates a simplified cross-section diagram of a conventionaltransportation system with FOUP 10 and support surface 20. FOUP 10comprises slots to hold a plurality of wafers, robotic lifting flange 17and manual lifting handles 16 for moving the FOUP.

FOUP 10 temporarily rests with its base plate 19 on support surface 20of the processing equipment, such as a load port, a container shelfwithin a buffer or a stocker, or elsewhere. A transportation vehicle canalso have such a support surface 20.

In order to align the position of FOUP 10 to the processing equipmentwith surface 20, kinematic coupling is used. A set of kinematic couplinggrooves 11, 12 (only 2 of 3 shown) in the base plate 19 of FOUP 10engages with kinematic coupling pins 21, 22 in support surface 20 (only2 of 3 shown). Grooves 11, 12 settle over pins 21, 22 to establishpoints of mechanical contact. The dimension of the grooves and of thepins are standardized so that FOUPs of various suppliers are compatiblewith each other (SEMI E 57 “Mechanical Specification for KinematicCouplings used to align and support 300-mm Wafer Carriers”).

There are instances where the FOUP is not placed on the support surfaceas specified in the standard. Hence, there is a need to monitor the FOUPplacement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified cross-section diagram of a conventionaltransportation system with FOUP and support surface;

FIG. 2 is a simplified cross-section diagram of a new transportationsystem with a wafer container and a support surface according to thepresent invention;

FIG. 3 is a simplified diagram of the wafer container according to thepresent invention;

FIG. 4 is a simplified diagram of the wafer container in an alternativeembodiment;

FIG. 5 is a simplified cross-section diagram of a support surface with akinemato-electric coupling pin; and

FIGS. 6ABC are simplified cross-section diagrams for an application thatuses the pin of FIG. 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 2 is a simplified cross-section diagram of a new wafertransportation system 100/200 with wafer container 100 and supportsurface 200 according to the present invention. Kinematic couplinggrooves 110, 120 and kinematic coupling pins 210, 220 are at leastpartially electrically conductive; in other words, “kinemato-electric”grooves and pins are presented.

Grooves 110, 120 in container 100 and pins 210, 220 on support surface200 (for holding container 100) do not only kinematically positioncontainer 100 in respect to support surface 200, but also allow toelectrically couple electric device 150 (“device”) associated withcontainer 100 to electrical circuit 250 associated with support surface200.

Preferably, device 150 is located within container 100 or attached tothe outside; circuit 250 is preferably, located outside surface 200. Forsimplicity, FIG. 2 does not illustrate the wafers, the lifting flange,and the manual lifting handles.

As mentioned above, the number and the shape of grooves and kinematiccoupling pins is standardized (e.g., 3 grooves/pins). By the presentinvention, number and shape remain unchanged. In other words, withmechanical handling and automation interfaces substantially unchanged,the transportation system of wafer container and support surface isdown-compatible to existing technology.

Although the following description uses for simplicity only the term“kinematic coupling pin”, it is intended that registration pins (SEMIstandard E62) can also be used to practice the present invention.

FIG. 3 is a simplified diagram of wafer container 100 (“container”)according to the present invention, viewed from below. Preferably,container 100 is Front Opening Unified Pod (FOUP); but this is notessential so that the present invention can also be applied to othertypes of containers. Container 100 is particularly advantageous whenused to hold semiconductor wafers having, for example, a diameter of 300mm or more. Different diameters (larger or smaller) can also be used.

In base plate 190, container 100 has at least first kinematic couplinggroove 110 (“groove”) with first groove surface 115. Groove 110 andfurther kinematic coupling groves 120 and 130 are provided to couplewith kinematic coupling pins on support surface 200 (cf. FIG. 2, pin 210with groove 110). Groove surface 115 has at least first electricallyconductive portion 111 that is electrically coupled to electrical device150 (“device”) located inside or outside wafer container 100.

As illustrated in the embodiment of FIG. 3, groove surface 115 of groove110 has second electrically conductive portion 112 that is substantiallyelectrically isolated from first electrically conductive portion 111 andthat is also electrically coupled to electrical device 150.Conveniently, electrically conductive portions 111 and 112 are arrangedsymmetrically in respect to groove symmetry line 119 (illustrated bypoint-dashed line).

Optionally, device 150 receives power via electrically conductiveportions 111 and 112 from circuit 250 (indicated by arrows 161 to device150); in other words, circuit 250 (cf. FIG. 2) can be a power supply. Itis an advantage of the present invention, that battery power for device150 is not required. However, the present invention does not precludethe use of a supply battery to power device 150.

Optionally, device 150 transmits signals that represent information viaelectrically conductive portions 111 and 112. Depending on theapplication, signal transmission can be unidirectional or bi-directional(cf. arrows 162 to and from device 150). When both options are used,device 150 receives power and transmits signals either consecutively(e.g., by time slots) or simultaneously (e.g., signal superimposition,frequency separation).

Conveniently, device 150 is a microprocessor, a stand-alone sensor, anyother combination of passive or active electrical device or acombination of microprocessor, sensor and other passive or activeelectrical devices. Device 150 can implement a variety of functions,such as, for example, and without the intention to be limiting,monitoring physical and other characteristics in container 100, forexample, pressure, temperature, organic contamination, inorganiccontamination, vacuum, nitrogen (after purging), monitoring leakage ofgases from the container; storing wafer related information such asprocess history, wafer identification, process parameters for earlier orfuture process steps, routing (local wafer-in-process database);counting the wafers; as well as other functions.

Monitoring and storing data can also be related to the container itself(e.g., cleaning history of the wafer, checking proper door closing,relative or absolute carrier location in the production facility(“fab”)).

Persons of skill in the art can also electrically couple otherelectrical devices to the grooves without departing from the presentinvention. Device 150 can be assembled to container 100 duringmanufacturing, e.g., during molding the base plate 190. Alternatively,device 150 can be mounted on container 100 after container manufacturingand can be removed if desired (temporarily mounting). Optionally, device150 and container 100 have their own mechanical, physical and electricalinterface design that provides interoperability and exchangeability.

FIG. 4 is a simplified diagram of wafer container 100 in an alternativeembodiment. Having a groove with separated conductive surfaces (cf. FIG.3) is convenient, but not essential. Container 100 has molded in baseplate 190 kinematic coupling groove 120 with groove surface 125 that isat least partially electrically conductive and electrically coupled todevice 150. Preferably, conductive portion 111 in groove 110 (cf. FIG.3) covers a larger area than in the embodiment of FIG. 3.

In an application to check the positioning of container 100 on surface200 (cf. FIG. 2), device 150 is formed by electrical conductive path 151extending from groove surface 115 to groove surface 125. The presence ofcontainer 100 in the predetermined position on support surface 200provides an electrically conductive loop with circuit 250. Theelectrical resistance R1 between grooves 110, 120 and hence betweenkinematic coupling pins 210, 220 of support surface 200 (cf. FIG. 2) ispredetermined. In other words, device 150 (i.e. path 151) is formed bybase plate 190. Conveniently, FIG. 4 also illustrates further paths 152,153 between grooves 120/130 and 130/110, respectively (resistance R2,R3). FIG. 5 is a simplified cross-section diagram of support surface 200with kinematic coupling pin 210 (“pin”). Pin 210 provides kinematiccoupling with kinematic coupling groove 110 in a wafer container 100(cf. FIGS. 2-4); pin 210 has first surface area 211 and second surfacearea 212 to kinematically couple to groove 110; area 211 issubstantially electrically isolated from area 212. Isolation can beprovided, for example, by making the complete body of pin 210 from asubstantially isolating material. A further example is illustrated inconnection with FIGS. 6ABC. Areas 211 and 212 are coupled to circuit 250(cf. FIG. 2).

FIG. 5 also shows, at least partially, support surface 200. In otherword, support surface 200 has at least first kinematic coupling pin 210to couple to corresponding first kinematic coupling groove 110 in baseplate 190 of wafer container 100 (cf. FIGS. 2-4). Support surface 200 ischaracterized by a pin 210 having at least first and second electricallyisolated areas 211, 212 to exchange electrical signals with container100 via first kinematic coupling groove 110.

FIGS. 6ABC are simplified cross-section diagrams for an application thatuses pin 210 of FIG. 5. In the example, pin 210 is shown with metalportions 213 and 214 (having surfaces 211, 212, respectively) that areisolated by isolation member 215. The application checks the properposition of container 100 on support surface 200. Shown from the A to C,groove 110 couples with pin 210 (normal case, FIG. 6A); grooves 110 doesnot couple with pin 210 at all (failure, FIG. 6B); and groove 110 doesonly partially couples with pin 210 (also failure, FIG. 6C). In the twofailure cases, circuit 250 (cf. FIG. 1) determines that the electricalresistance between surfaces 211 and 212 is above a predeterminedthreshold and, preferably, issues a warning signal.

In other words, electrically isolated surface areas 211 and 212 of pin210 are electrically coupled to evaluation circuit 250 (cf. FIG. 1) thatmeasures the electrical resistance between areas 211 and 212 to indicatethe kinematic coupling between groove 110 in container 100 when anelectrical conductive path is established via area 211, groove 110 andsecond surface area 212.

In other words, viewing this application from the electrical device 150,that in FIGS. 6ABC is formed by groove surface 110 itself, theapplication is presented as follows: An electrical conductive pathextending between electrically conductive portions 111 and 112 of groove110, so that kinematic coupling of groove 110 with pin 210 (of surface200) provides an electrically conductive loop having a predeterminedresistance (e.g., substantially zero) between portions 111 and 112.

More generally, a predetermined resistance on one side (e.g., groove) ismeasured from a measurement device at the other side (e.g., pin). It isalso within the scope of the invention to measure the resistance acrossa single-surface pin by device 150 (resistance sensor) across a doublesurface groove (cf. surfaces 111, 112 in FIG. 2).

Providing a pin with isolated surface areas 211, 212 is convenient, butnot essential for the present invention. Returning in the explanation toFIG. 2, support surface 200 for holding container 100 has kinematiccoupling pins 210 and 220 to couple to corresponding kinematic couplinggrooves 110 and 120, respectively, in plate 190. Pins 210, 220 each areelectrically conductive but electrically isolated from each other toexchange electrical signals with container 100 via kinematic couplinggrooves 110 120 and 120.

In a container position sensing application, these electrical signalsrepresent a measured resistance between pins 210 and 220 and therebyselectively indicate the presence or the absence of wafer container 100on surface 200.

Having described details, a method for operating transportation system100/200 (cf. FIGS. 2-6, wafer container 100 and support surface 200) issummarized as comprising the following first and second steps:

As a first step, wafer container 100 (plurality of kinematic couplinggrooves 110, 120, 130, at least partially electrically conductive) isplaced on support surface 200 (plurality of corresponding kinematiccoupling pins 210, 220, 230, also at least partially electricallyconductive) to kinematically couple the grooves with the pins; and as asecond step, at least one step selected from a group of the followingsteps is executed:

measuring the electrical resistance across a single groove via a singlepin (that has electrically isolated parts; cf. FIGS. 6ABC);

measuring the electrical resistance between two grooves via twocorresponding pins (cf. FIG. 4);

sending power to an electrical device (e.g., device 150) within thewafer container from the single pin that has electrically isolated parts(cf. FIGS. 2, 3, 5);

sending power to the electrical device via two pins (cf. FIG. 2);

sending a signal from the electrical device via the single pin (that haselectrically isolated parts, cf. FIGS. 3, 5, 6); and

sending a signal from the electrical device via two pins (cf. FIGS. 2,4).

To summarize the transportation system (e.g., container 100 with groovesand surface 200 with coupling pins), the system is characterized in thatthe grooves and the pins are at least partially electrically conductiveto couple an electric device associated with the wafer container to anelectrical circuit associated with the support surface.

While the invention has been described in terms of particularstructures, steps, devices and materials, those of skill in the art willunderstand based on the description herein that it is not limited merelyto such examples and that the full scope of the invention is properlydetermined by the claims that follow.

What is claimed is:
 1. A wafer container having in a base plate at leasta first kinematic coupling groove with a first groove surface, saidwafer container characterized in that said first groove surface has afirst electrically conductive portion that is electrically coupled to anelectrical device in said wafer container.
 2. The wafer container ofclaim 1 wherein said groove surface of said first kinematic couplinggroove has a second electrically conductive portion that issubstantially electrically isolated from said first electricallyconductive portion and that is also electrically coupled to saidelectrical device.
 3. The wafer container of claim 2 wherein saidelectrical device receives power via said first and second electricallyconductive portions.
 4. The wafer container of claim 3 wherein saidelectrical device transmits signals via said first and secondelectrically conductive portions.
 5. The wafer container of claim 4wherein said electrical device receives power and transmits signalsconsecutively or simultaneously.
 6. The wafer container of claim 5,wherein said electrical device is a microprocessor.
 7. The wafercontainer of claim 6, wherein said electrical device is a sensor. 8.Wafer container of claim 1 being a Front Opening Unified Pod (FOUP). 9.Wafer container of claim 2 wherein said first and second electricallyconductive portions are arranged symmetrically in respect to a groovesymmetry line.
 10. The wafer container of claim 2 wherein saidelectrical device is an electrical conductive path extending betweensaid first and second electrically conductive portions, so thatkinematic coupling of said first groove with a kinematic coupling pin ofa support surface provides an electrically conductive loop having apredetermined resistance between said first and second portions.
 11. Thewafer container of claim 1 having in said base plate a second kinematiccoupling groove with a second groove surface, wherein said second groovesurface is at least partially electrically conductive and electricallycoupled to said electrical device.
 12. A support surface for holding awafer container, said support surface having first and second kinematiccoupling pins to couple to corresponding first and second kinematiccoupling grooves in a base plate of said wafer container, said supportsurface characterized in that said kinematic coupling pins each areelectrically conductive but electrically isolated from each other toexchange electrical signals with said container via said first andsecond kinematic coupling grooves.
 13. A method for operating atransportation system of a wafer container and a support surface, saidmethod comprising the following first and second steps: first, placingsaid wafer container having a plurality of kinematic coupling groovesthat are least partially electrically conductive on said support surfacethat has a plurality of corresponding kinematic coupling pins that arealso at least partially electrically conductive to kinematically couplesaid grooves with said pins, and second, at least one step selected froma group of the following steps: sending power to an electrical devicewithin said wafer container from a single pin that has electricallyisolated parts; sending power to said electrical device via two pins;sending a signal from said electrical device via said single pin thathas electrically isolated parts; and sending a signal from saidelectrical device via two pins.
 14. Transportation system with a wafercontainer and support surface, said wafer container having kinematiccoupling grooves, said support surface having kinematic coupling pins,said transportation system characterized in that said grooves and pinsare at least partially electrically conductive to couple an electricdevice associated with said wafer container to an electrical circuitassociated with said support surface.